Learn English – the meaning of “here” at the end of a sentence and how should it be used

All modals have several meanings. Most common are

• the Epistemic sense of a modal, which refers to logical conclusions
  This must be the place, This can't be the place, This would be the place.

• The Deontic sense of a modal, which refers to sociocultural obligations and affordances
  You must be careful, You can't do that, He wouldn't dare.

The first three uses of would are, as @Cathy points out, equivalent to epistemic must.
I.e, like all epistemic modals, they state a conclusion made by the speaker from
some kind of evidence or presupposition, rather than an assertion of fact.

It seems likely that (1-2), for instance, are short for something like

• (if I were to guess, I would say that) that would be John/Ram.

(3) is almost the same -- (If I were to guess, I would say that) they were ...

(4) and (5) are different. For one thing, they're stressed main verbs, not auxiliaries.
For another, they're deontic, not epistemic. Deontic would has to do with being willing
(will (n) and will (v) and willing and willful and would are all from the same root).

So, to say that somebody would do something (with a stressed would, and especially with a deleted main verb, as in 4) is to say that they are willing (and therefore likely) to do it under certain conditions.

Note that in (5) there are two modals -- deontic would and deontic have to, so what's being said is that he was willing, and indeed obliged, to say that under certain conditions.

And these are not the only possible senses of would, either.